anonymous
  • anonymous
(cos A + cos b)^2 + (sin A + sin B)^2=?
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
jamiebookeater
  • jamiebookeater
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
anonymous
  • anonymous
@apoorvk @satellite73 @A.Avinash_Goutham @ajprincess @AndrewNJ
apoorvk
  • apoorvk
okay, expand the two whole-squares, it's simple enough...
anonymous
  • anonymous
the options are 4cos^2(a-b/2) 4 sin a/2 cos b/2

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

anonymous
  • anonymous
|dw:1339426035616:dw|
anonymous
  • anonymous
@apoorvk after expanding i got this then next..............
apoorvk
  • apoorvk
great, now.. cosAcosB + sinAsinB = cos(A-B) Use this^
anonymous
  • anonymous
ugh, trig identities are a drag. Even after deriving them myself I simply CANNOT seem to memorize them
anonymous
  • anonymous
spread it so we have (cosa)^2+(cosb)^2+2(cosa)(cosb)+(sina)^2+(sinb)^2+2(sina)(sinb) =2+2cos(a-b)
anonymous
  • anonymous
(cosa)^2+(sina)^2=1 (cosb)^2+(sinb)^2=1 (cosa)(cosb)+(sina)(sinb)=cos(a-b)
anonymous
  • anonymous
ok @apoorvk so it is not over yet!!@
anonymous
  • anonymous
Continuing from where @AndrewNJ left, \[2(1+\cos(a-b))\] now we know that \[1 + \cos 2a = 2 \cos^2 a\] Now try :D
anonymous
  • anonymous
@shivam_bhalla did nt understand!
anonymous
  • anonymous
= \[2(1+\cos 2\frac{(a-b)}{2})\] Now we have a identity, \[1 + \cos 2x = 2 \cos^2 x\] in your case, \[x = \frac{a-b}{2}\] Now try
anonymous
  • anonymous
i got it thxx @shivam_bhalla
anonymous
  • anonymous
Your welcome :)
anonymous
  • anonymous

Looking for something else?

Not the answer you are looking for? Search for more explanations.